/* $NetBSD: dhcrelay.c,v 1.2.6.1 2024/02/29 11:39:57 martin Exp $ */ /* dhcrelay.c DHCP/BOOTP Relay Agent. */ /* * Copyright(c) 2004-2022 by Internet Systems Consortium, Inc.("ISC") * Copyright(c) 1997-2003 by Internet Software Consortium * * This Source Code Form is subject to the terms of the Mozilla Public * License, v. 2.0. If a copy of the MPL was not distributed with this * file, You can obtain one at http://mozilla.org/MPL/2.0/. * * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. * * Internet Systems Consortium, Inc. * PO Box 360 * Newmarket, NH 03857 USA * * https://www.isc.org/ * */ #include __RCSID("$NetBSD: dhcrelay.c,v 1.2.6.1 2024/02/29 11:39:57 martin Exp $"); #include "dhcpd.h" #include #include #include #include TIME default_lease_time = 43200; /* 12 hours... */ TIME max_lease_time = 86400; /* 24 hours... */ struct tree_cache *global_options[256]; struct option *requested_opts[2]; /* Needed to prevent linking against conflex.c. */ int lexline; int lexchar; char *token_line; char *tlname; const char *path_dhcrelay_pid = _PATH_DHCRELAY_PID; isc_boolean_t no_dhcrelay_pid = ISC_FALSE; /* False (default) => we write and use a pid file */ isc_boolean_t no_pid_file = ISC_FALSE; int bogus_agent_drops = 0; /* Packets dropped because agent option field was specified and we're not relaying packets that already have an agent option specified. */ int bogus_giaddr_drops = 0; /* Packets sent to us to relay back to a client, but with a bogus giaddr. */ int client_packets_relayed = 0; /* Packets relayed from client to server. */ int server_packet_errors = 0; /* Errors sending packets to servers. */ int server_packets_relayed = 0; /* Packets relayed from server to client. */ int client_packet_errors = 0; /* Errors sending packets to clients. */ int add_agent_options = 0; /* If nonzero, add relay agent options. */ int add_rfc3527_suboption = 0; /* If nonzero, add RFC3527 link selection sub-option. */ int agent_option_errors = 0; /* Number of packets forwarded without agent options because there was no room. */ int drop_agent_mismatches = 0; /* If nonzero, drop server replies that don't have matching circuit-id's. */ int corrupt_agent_options = 0; /* Number of packets dropped because relay agent information option was bad. */ int missing_agent_option = 0; /* Number of packets dropped because no RAI option matching our ID was found. */ int bad_circuit_id = 0; /* Circuit ID option in matching RAI option did not match any known circuit ID. */ int missing_circuit_id = 0; /* Circuit ID option in matching RAI option was missing. */ int max_hop_count = 10; /* Maximum hop count */ int no_daemon = 0; int dfd[2] = { -1, -1 }; #ifdef DHCPv6 /* Force use of DHCPv6 interface-id option. */ isc_boolean_t use_if_id = ISC_FALSE; #endif /* Maximum size of a packet with agent options added. */ int dhcp_max_agent_option_packet_length = DHCP_MTU_MIN; /* What to do about packets we're asked to relay that already have a relay option: */ enum { forward_and_append, /* Forward and append our own relay option. */ forward_and_replace, /* Forward, but replace theirs with ours. */ forward_untouched, /* Forward without changes. */ discard } agent_relay_mode = forward_and_replace; extern u_int16_t local_port; extern u_int16_t remote_port; /* Relay agent server list. */ struct server_list { struct server_list *next; struct sockaddr_in to; } *servers; struct interface_info *uplink = NULL; isc_boolean_t use_fake_gw = ISC_FALSE; struct in_addr gw = {0}; #ifdef DHCPv6 struct stream_list { struct stream_list *next; struct interface_info *ifp; struct sockaddr_in6 link; int id; } *downstreams, *upstreams; #ifndef UNIT_TEST static struct stream_list *parse_downstream(char *); static struct stream_list *parse_upstream(char *); static void setup_streams(void); #endif /* UNIT_TEST */ /* * A pointer to a subscriber id to add to the message we forward. * This is primarily for testing purposes as we only have one id * for the entire relay and don't determine one per client which * would be more useful. */ char *dhcrelay_sub_id = NULL; #endif libdhcp_callbacks_t dhcrelay_callbacks = { &local_port, &remote_port, classify, check_collection, dhcp, #ifdef DHCPv6 dhcpv6, #endif /* DHCPv6 */ bootp, find_class, parse_allow_deny, dhcp_set_control_state, }; #ifndef UNIT_TEST static void do_relay4(struct interface_info *, struct dhcp_packet *, unsigned int, unsigned int, struct iaddr, struct hardware *); #endif /* UNIT_TEST */ extern int add_relay_agent_options(struct interface_info *, struct dhcp_packet *, unsigned, struct in_addr); extern int find_interface_by_agent_option(struct dhcp_packet *, struct interface_info **, u_int8_t *, int); extern int strip_relay_agent_options(struct interface_info *, struct interface_info **, struct dhcp_packet *, unsigned); #ifndef UNIT_TEST static void request_v4_interface(const char* name, int flags); static const char copyright[] = "Copyright 2004-2022 Internet Systems Consortium."; static const char arr[] = "All rights reserved."; static const char message[] = "Internet Systems Consortium DHCP Relay Agent"; static const char url[] = "For info, please visit https://www.isc.org/software/dhcp/"; char *progname; #ifdef DHCPv6 #ifdef RELAY_PORT #define DHCRELAY_USAGE \ "Usage: %s [-4] [-d] [-q] [-a] [-D]\n" \ " [-A ] [-c ]\n" \ " [-p | -rp ]\n" \ " [-pf ] [--no-pid]\n"\ " [-m append|replace|forward|discard]\n" \ " [-i interface0 [ ... -i interfaceN]\n" \ " [-iu interface0 [ ... -iu interfaceN]\n" \ " [-id interface0 [ ... -id interfaceN]\n" \ " [-U interface] [-g ]\n" \ " server0 [ ... serverN]\n\n" \ " %s -6 [-d] [-q] [-I] [-c ]\n" \ " [-p | -rp ]\n" \ " [-pf ] [--no-pid]\n" \ " [-s ]\n" \ " -l lower0 [ ... -l lowerN]\n" \ " -u upper0 [ ... -u upperN]\n" \ " lower (client link): [address%%]interface[#index]\n" \ " upper (server link): [address%%]interface\n\n" \ " %s {--version|--help|-h}" #else #define DHCRELAY_USAGE \ "Usage: %s [-4] [-d] [-q] [-a] [-D]\n" \ " [-A ] [-c ] [-p ]\n" \ " [-pf ] [--no-pid]\n"\ " [-m append|replace|forward|discard]\n" \ " [-i interface0 [ ... -i interfaceN]\n" \ " [-iu interface0 [ ... -iu interfaceN]\n" \ " [-id interface0 [ ... -id interfaceN]\n" \ " [-U interface] [-g ]\n" \ " server0 [ ... serverN]\n\n" \ " %s -6 [-d] [-q] [-I] [-c ] [-p ]\n" \ " [-pf ] [--no-pid]\n" \ " [-s ]\n" \ " -l lower0 [ ... -l lowerN]\n" \ " -u upper0 [ ... -u upperN]\n" \ " lower (client link): [address%%]interface[#index]\n" \ " upper (server link): [address%%]interface\n\n" \ " %s {--version|--help|-h}" #endif #else /* !DHCPv6 */ #ifdef RELAY_PORT #define DHCRELAY_USAGE \ "Usage: %s [-d] [-q] [-a] [-D] [-A ] [-c ]\n" \ " [-p | -rp ]\n" \ " [-pf ] [--no-pid]\n" \ " [-m append|replace|forward|discard]\n" \ " [-i interface0 [ ... -i interfaceN]\n" \ " [-iu interface0 [ ... -iu interfaceN]\n" \ " [-id interface0 [ ... -id interfaceN]\n" \ " [-U interface] [-g ]\n" \ " server0 [ ... serverN]\n\n" \ " %s {--version|--help|-h}" #else #define DHCRELAY_USAGE \ "Usage: %s [-d] [-q] [-a] [-D] [-A ] [-c ] [-p ]\n" \ " [-pf ] [--no-pid]\n" \ " [-m append|replace|forward|discard]\n" \ " [-i interface0 [ ... -i interfaceN]\n" \ " [-iu interface0 [ ... -iu interfaceN]\n" \ " [-id interface0 [ ... -id interfaceN]\n" \ " [-U interface] [-g ]\n" \ " server0 [ ... serverN]\n\n" \ " %s {--version|--help|-h}" #endif #endif /*! * * \brief Print the generic usage message * * If the user has provided an incorrect command line print out * the description of the command line. The arguments provide * a way for the caller to request more specific information about * the error be printed as well. Mostly this will be that some * command doesn't include its argument. * * \param sfmt - The basic string and format for the specific error * \param sarg - Generally the offending argument from the command line. * * \return Nothing */ #include __RCSID("$NetBSD: dhcrelay.c,v 1.2.6.1 2024/02/29 11:39:57 martin Exp $"); static const char use_noarg[] = "No argument for command: %s"; #ifdef RELAY_PORT static const char use_port_defined[] = "Port already set, %s inappropriate"; #if !defined (USE_BPF_RECEIVE) && !defined (USE_LPF_RECEIVE) static const char bpf_sock_support[] = "Only LPF and BPF are supported: %s"; #endif #endif #ifdef DHCPv6 static const char use_badproto[] = "Protocol already set, %s inappropriate"; static const char use_v4command[] = "Command not used for DHCPv6: %s"; static const char use_v6command[] = "Command not used for DHCPv4: %s"; #endif static void usage(const char *sfmt, const char *sarg) { log_info("%s %s", message, PACKAGE_VERSION); log_info(copyright); log_info(arr); log_info(url); /* If desired print out the specific error message */ #ifdef PRINT_SPECIFIC_CL_ERRORS if (sfmt != NULL) log_error(sfmt, sarg); #endif log_fatal(DHCRELAY_USAGE, #ifdef DHCPv6 isc_file_basename(progname), #endif isc_file_basename(progname), isc_file_basename(progname)); } int main(int argc, char **argv) { isc_result_t status; struct servent *ent; struct server_list *sp = NULL; char *service_local = NULL, *service_remote = NULL; u_int16_t port_local = 0, port_remote = 0; int quiet = 0; int fd; int i; #ifdef RELAY_PORT int port_defined = 0; #endif #ifdef DHCPv6 struct stream_list *sl = NULL; int local_family_set = 0; #endif libdhcp_callbacks_register(&dhcrelay_callbacks); #ifdef OLD_LOG_NAME progname = "dhcrelay"; #else progname = argv[0]; #endif /* Make sure that file descriptors 0(stdin), 1,(stdout), and 2(stderr) are open. To do this, we assume that when we open a file the lowest available file descriptor is used. */ fd = open("/dev/null", O_RDWR); if (fd == 0) fd = open("/dev/null", O_RDWR); if (fd == 1) fd = open("/dev/null", O_RDWR); if (fd == 2) log_perror = 0; /* No sense logging to /dev/null. */ else if (fd != -1) close(fd); openlog(isc_file_basename(progname), DHCP_LOG_OPTIONS, LOG_DAEMON); #if !defined(DEBUG) setlogmask(LOG_UPTO(LOG_INFO)); #endif /* Parse arguments changing no_daemon */ for (i = 1; i < argc; i++) { if (!strcmp(argv[i], "-d")) { no_daemon = 1; } else if (!strcmp(argv[i], "--version")) { log_info("isc-dhcrelay-%s", PACKAGE_VERSION); exit(0); } else if (!strcmp(argv[i], "--help") || !strcmp(argv[i], "-h")) { log_info(DHCRELAY_USAGE, #ifdef DHCPv6 isc_file_basename(progname), #endif isc_file_basename(progname), isc_file_basename(progname)); exit(0); } } /* When not forbidden prepare to become a daemon */ if (!no_daemon) { int pid; if (pipe(dfd) == -1) log_fatal("Can't get pipe: %m"); if ((pid = fork ()) < 0) log_fatal("Can't fork daemon: %m"); if (pid != 0) { /* Parent: wait for the child to start */ int n; (void) close(dfd[1]); do { char buf; n = read(dfd[0], &buf, 1); if (n == 1) _exit(0); } while (n == -1 && errno == EINTR); _exit(1); } /* Child */ (void) close(dfd[0]); } /* Set up the isc and dns library managers */ status = dhcp_context_create(DHCP_CONTEXT_PRE_DB, NULL, NULL); if (status != ISC_R_SUCCESS) log_fatal("Can't initialize context: %s", isc_result_totext(status)); /* Set up the OMAPI. */ status = omapi_init(); if (status != ISC_R_SUCCESS) log_fatal("Can't initialize OMAPI: %s", isc_result_totext(status)); /* Set up the OMAPI wrappers for the interface object. */ interface_setup(); for (i = 1; i < argc; i++) { if (!strcmp(argv[i], "-4")) { #ifdef DHCPv6 if (local_family_set && (local_family == AF_INET6)) { usage(use_badproto, "-4"); } local_family_set = 1; local_family = AF_INET; } else if (!strcmp(argv[i], "-6")) { if (local_family_set && (local_family == AF_INET)) { usage(use_badproto, "-6"); } local_family_set = 1; local_family = AF_INET6; #endif } else if (!strcmp(argv[i], "-d")) { /* no_daemon = 1; */ } else if (!strcmp(argv[i], "-q")) { quiet = 1; quiet_interface_discovery = 1; } else if (!strcmp(argv[i], "-p")) { if (++i == argc) usage(use_noarg, argv[i-1]); #ifdef RELAY_PORT if (port_defined) usage(use_port_defined, argv[i-1]); port_defined = 1; #endif local_port = validate_port(argv[i]); log_debug("binding to user-specified port %d", ntohs(local_port)); #ifdef RELAY_PORT } else if (!strcmp(argv[i], "-rp")) { if (++i == argc) usage(use_noarg, argv[i-1]); if (port_defined) usage(use_port_defined, argv[i-1]); port_defined = 1; relay_port = validate_port(argv[i]); log_debug("binding to user-specified relay port %d", ntohs(relay_port)); add_agent_options = 1; #endif } else if (!strcmp(argv[i], "-c")) { int hcount; if (++i == argc) usage(use_noarg, argv[i-1]); hcount = atoi(argv[i]); if (hcount <= 255) max_hop_count= hcount; else usage("Bad hop count to -c: %s", argv[i]); } else if (!strcmp(argv[i], "-i")) { #ifdef DHCPv6 if (local_family_set && (local_family == AF_INET6)) { usage(use_v4command, argv[i]); } local_family_set = 1; local_family = AF_INET; #endif if (++i == argc) { usage(use_noarg, argv[i-1]); } request_v4_interface(argv[i], INTERFACE_STREAMS); } else if (!strcmp(argv[i], "-iu")) { #ifdef DHCPv6 if (local_family_set && (local_family == AF_INET6)) { usage(use_v4command, argv[i]); } local_family_set = 1; local_family = AF_INET; #endif if (++i == argc) { usage(use_noarg, argv[i-1]); } request_v4_interface(argv[i], INTERFACE_UPSTREAM); } else if (!strcmp(argv[i], "-id")) { #ifdef DHCPv6 if (local_family_set && (local_family == AF_INET6)) { usage(use_v4command, argv[i]); } local_family_set = 1; local_family = AF_INET; #endif if (++i == argc) { usage(use_noarg, argv[i-1]); } request_v4_interface(argv[i], INTERFACE_DOWNSTREAM); } else if (!strcmp(argv[i], "-a")) { #ifdef DHCPv6 if (local_family_set && (local_family == AF_INET6)) { usage(use_v4command, argv[i]); } local_family_set = 1; local_family = AF_INET; #endif add_agent_options = 1; } else if (!strcmp(argv[i], "-A")) { #ifdef DHCPv6 if (local_family_set && (local_family == AF_INET6)) { usage(use_v4command, argv[i]); } local_family_set = 1; local_family = AF_INET; #endif if (++i == argc) usage(use_noarg, argv[i-1]); dhcp_max_agent_option_packet_length = atoi(argv[i]); if (dhcp_max_agent_option_packet_length > DHCP_MTU_MAX) log_fatal("%s: packet length exceeds " "longest possible MTU\n", argv[i]); } else if (!strcmp(argv[i], "-m")) { #ifdef DHCPv6 if (local_family_set && (local_family == AF_INET6)) { usage(use_v4command, argv[i]); } local_family_set = 1; local_family = AF_INET; #endif if (++i == argc) usage(use_noarg, argv[i-1]); if (!strcasecmp(argv[i], "append")) { agent_relay_mode = forward_and_append; } else if (!strcasecmp(argv[i], "replace")) { agent_relay_mode = forward_and_replace; } else if (!strcasecmp(argv[i], "forward")) { agent_relay_mode = forward_untouched; } else if (!strcasecmp(argv[i], "discard")) { agent_relay_mode = discard; } else usage("Unknown argument to -m: %s", argv[i]); } else if (!strcmp(argv [i], "-U")) { if (++i == argc) usage(use_noarg, argv[i-1]); if (uplink) { usage("more than one uplink (-U) specified: %s" ,argv[i]); } /* Allocate the uplink interface */ status = interface_allocate(&uplink, MDL); if (status != ISC_R_SUCCESS) { log_fatal("%s: uplink interface_allocate: %s", argv[i], isc_result_totext(status)); } if (strlen(argv[i]) >= sizeof(uplink->name)) { log_fatal("%s: uplink name too long," " it cannot exceed: %ld characters", argv[i], (long)(sizeof(uplink->name) - 1)); } uplink->name[sizeof(uplink->name) - 1] = 0x00; strncpy(uplink->name, argv[i], sizeof(uplink->name) - 1); interface_snorf(uplink, (INTERFACE_REQUESTED | INTERFACE_STREAMS)); /* Turn on -a, in case they don't do so explicitly */ add_agent_options = 1; add_rfc3527_suboption = 1; } else if (!strcmp(argv[i], "-g")) { if (++i == argc) usage(use_noarg, argv[i-1]); #ifdef DHCPv6 if (local_family_set && (local_family == AF_INET6)) { usage(use_v4command, argv[i]); } local_family_set = 1; local_family = AF_INET; #endif if (inet_pton(AF_INET, argv[i], &gw) <= 0) { usage("Invalid gateway address '%s'", argv[i]); } else { use_fake_gw = ISC_TRUE; } } else if (!strcmp(argv[i], "-D")) { #ifdef DHCPv6 if (local_family_set && (local_family == AF_INET6)) { usage(use_v4command, argv[i]); } local_family_set = 1; local_family = AF_INET; #endif drop_agent_mismatches = 1; #ifdef DHCPv6 } else if (!strcmp(argv[i], "-I")) { if (local_family_set && (local_family == AF_INET)) { usage(use_v6command, argv[i]); } local_family_set = 1; local_family = AF_INET6; use_if_id = ISC_TRUE; } else if (!strcmp(argv[i], "-l")) { if (local_family_set && (local_family == AF_INET)) { usage(use_v6command, argv[i]); } local_family_set = 1; local_family = AF_INET6; if (downstreams != NULL) use_if_id = ISC_TRUE; if (++i == argc) usage(use_noarg, argv[i-1]); sl = parse_downstream(argv[i]); sl->next = downstreams; downstreams = sl; } else if (!strcmp(argv[i], "-u")) { if (local_family_set && (local_family == AF_INET)) { usage(use_v6command, argv[i]); } local_family_set = 1; local_family = AF_INET6; if (++i == argc) usage(use_noarg, argv[i-1]); sl = parse_upstream(argv[i]); sl->next = upstreams; upstreams = sl; } else if (!strcmp(argv[i], "-s")) { if (local_family_set && (local_family == AF_INET)) { usage(use_v6command, argv[i]); } local_family_set = 1; local_family = AF_INET6; if (++i == argc) usage(use_noarg, argv[i-1]); dhcrelay_sub_id = argv[i]; #endif } else if (!strcmp(argv[i], "-pf")) { if (++i == argc) usage(use_noarg, argv[i-1]); path_dhcrelay_pid = argv[i]; no_dhcrelay_pid = ISC_TRUE; } else if (!strcmp(argv[i], "--no-pid")) { no_pid_file = ISC_TRUE; } else if (argv[i][0] == '-') { usage("Unknown command: %s", argv[i]); } else { struct hostent *he; struct in_addr ia, *iap = NULL; #ifdef DHCPv6 if (local_family_set && (local_family == AF_INET6)) { usage(use_v4command, argv[i]); } local_family_set = 1; local_family = AF_INET; #endif if (inet_aton(argv[i], &ia)) { iap = &ia; } else { he = gethostbyname(argv[i]); if (!he) { log_error("%s: host unknown", argv[i]); } else { iap = ((struct in_addr *) he->h_addr_list[0]); } } if (iap) { sp = ((struct server_list *) dmalloc(sizeof *sp, MDL)); if (!sp) log_fatal("no memory for server.\n"); sp->next = servers; servers = sp; memcpy(&sp->to.sin_addr, iap, sizeof *iap); } } } #if defined(RELAY_PORT) && \ !defined (USE_BPF_RECEIVE) && !defined (USE_LPF_RECEIVE) if (relay_port && (local_family == AF_INET)) usage(bpf_sock_support, "-rp"); #endif /* * If the user didn't specify a pid file directly * find one from environment variables or defaults */ if (no_dhcrelay_pid == ISC_FALSE) { if (local_family == AF_INET) { path_dhcrelay_pid = getenv("PATH_DHCRELAY_PID"); if (path_dhcrelay_pid == NULL) path_dhcrelay_pid = _PATH_DHCRELAY_PID; } #ifdef DHCPv6 else { path_dhcrelay_pid = getenv("PATH_DHCRELAY6_PID"); if (path_dhcrelay_pid == NULL) path_dhcrelay_pid = _PATH_DHCRELAY6_PID; } #endif } if (!quiet) { log_info("%s %s", message, PACKAGE_VERSION); log_info(copyright); log_info(arr); log_info(url); } else log_perror = 0; /* Set default port */ if (local_family == AF_INET) { service_local = "bootps"; service_remote = "bootpc"; port_local = htons(67); port_remote = htons(68); } #ifdef DHCPv6 else { service_local = "dhcpv6-server"; service_remote = "dhcpv6-client"; port_local = htons(547); port_remote = htons(546); } #endif if (!local_port) { ent = getservbyname(service_local, "udp"); if (ent) local_port = ent->s_port; else local_port = port_local; ent = getservbyname(service_remote, "udp"); if (ent) remote_port = ent->s_port; else remote_port = port_remote; endservent(); } if (local_family == AF_INET) { /* We need at least one server */ if (servers == NULL) { log_fatal("No servers specified."); } /* Set up the server sockaddrs. */ for (sp = servers; sp; sp = sp->next) { sp->to.sin_port = local_port; sp->to.sin_family = AF_INET; #ifdef HAVE_SA_LEN sp->to.sin_len = sizeof sp->to; #endif } } #ifdef DHCPv6 else { unsigned code; /* We need at least one upstream and one downstream interface */ if (upstreams == NULL || downstreams == NULL) { log_info("Must specify at least one lower " "and one upper interface.\n"); usage(NULL, NULL); } /* Set up the initial dhcp option universe. */ initialize_common_option_spaces(); /* Check requested options. */ code = D6O_RELAY_MSG; if (!option_code_hash_lookup(&requested_opts[0], dhcpv6_universe.code_hash, &code, 0, MDL)) log_fatal("Unable to find the RELAY_MSG " "option definition."); code = D6O_INTERFACE_ID; if (!option_code_hash_lookup(&requested_opts[1], dhcpv6_universe.code_hash, &code, 0, MDL)) log_fatal("Unable to find the INTERFACE_ID " "option definition."); } #endif /* Become a daemon... */ if (!no_daemon) { char buf = 0; FILE *pf; int pfdesc; log_perror = 0; /* Signal parent we started successfully. */ if (dfd[0] != -1 && dfd[1] != -1) { if (write(dfd[1], &buf, 1) != 1) log_fatal("write to parent: %m"); (void) close(dfd[1]); dfd[0] = dfd[1] = -1; } /* Create the pid file. */ if (no_pid_file == ISC_FALSE) { pfdesc = open(path_dhcrelay_pid, O_CREAT | O_TRUNC | O_WRONLY, 0644); if (pfdesc < 0) { log_error("Can't create %s: %m", path_dhcrelay_pid); } else { pf = fdopen(pfdesc, "w"); if (!pf) log_error("Can't fdopen %s: %m", path_dhcrelay_pid); else { fprintf(pf, "%ld\n",(long)getpid()); fclose(pf); } } } (void) close(0); (void) close(1); (void) close(2); (void) setsid(); IGNORE_RET (chdir("/")); } /* Set up the isc and dns library managers */ status = dhcp_context_create(DHCP_CONTEXT_PRE_DB | DHCP_CONTEXT_POST_DB, NULL, NULL); if (status != ISC_R_SUCCESS) log_fatal("Can't initialize context: %s", isc_result_totext(status)); /* Get the current time... */ gettimeofday(&cur_tv, NULL); /* Discover all the network interfaces. */ discover_interfaces(DISCOVER_RELAY); #ifdef DHCPv6 if (local_family == AF_INET6) setup_streams(); #endif /* Set up the packet handler... */ if (local_family == AF_INET) bootp_packet_handler = do_relay4; #ifdef DHCPv6 else dhcpv6_packet_handler = do_packet6; #endif #if defined(ENABLE_GENTLE_SHUTDOWN) /* no signal handlers until we deal with the side effects */ /* install signal handlers */ signal(SIGINT, dhcp_signal_handler); /* control-c */ signal(SIGTERM, dhcp_signal_handler); /* kill */ #endif /* Start dispatching packets and timeouts... */ dispatch(); /* In fact dispatch() never returns. */ return (0); } static void do_relay4(struct interface_info *ip, struct dhcp_packet *packet, unsigned int length, unsigned int from_port, struct iaddr from, struct hardware *hfrom) { struct server_list *sp; struct sockaddr_in to; struct interface_info *out; struct hardware hto, *htop; if (packet->hlen > sizeof packet->chaddr) { log_info("Discarding packet with invalid hlen, received on " "%s interface.", ip->name); return; } if (ip->address_count < 1 || ip->addresses == NULL) { log_info("Discarding packet received on %s interface that " "has no IPv4 address assigned.", ip->name); return; } /* Find the interface that corresponds to the giaddr in the packet. */ if (packet->giaddr.s_addr) { for (out = interfaces; out; out = out->next) { int i; for (i = 0 ; i < out->address_count ; i++ ) { if (out->addresses[i].s_addr == packet->giaddr.s_addr) { i = -1; break; } } if (i == -1) break; } } else { out = NULL; } /* If it's a bootreply, forward it to the client. */ if (packet->op == BOOTREPLY) { if (!(ip->flags & INTERFACE_UPSTREAM)) { log_debug("Dropping reply received on %s", ip->name); return; } log_debug("BOOTREPLY giaddr: %s\n", inet_ntoa(packet->giaddr)); if (!(packet->flags & htons(BOOTP_BROADCAST)) && can_unicast_without_arp(out)) { to.sin_addr = packet->yiaddr; to.sin_port = remote_port; /* and hardware address is not broadcast */ htop = &hto; } else { to.sin_addr.s_addr = htonl(INADDR_BROADCAST); to.sin_port = remote_port; /* hardware address is broadcast */ htop = NULL; } to.sin_family = AF_INET; #ifdef HAVE_SA_LEN to.sin_len = sizeof to; #endif memcpy(&hto.hbuf[1], packet->chaddr, packet->hlen); hto.hbuf[0] = packet->htype; hto.hlen = packet->hlen + 1; /* Wipe out the agent relay options and, if possible, figure out which interface to use based on the contents of the option that we put on the request to which the server is replying. */ if (!(length = strip_relay_agent_options(ip, &out, packet, length))) return; if (!out) { log_error("Packet to bogus giaddr %s.\n", inet_ntoa(packet->giaddr)); ++bogus_giaddr_drops; return; } if (use_fake_gw) { packet->giaddr = gw; } if (send_packet(out, NULL, packet, length, out->addresses[0], &to, htop) < 0) { ++server_packet_errors; } else { log_debug("Forwarded BOOTREPLY for %s to %s", print_hw_addr(packet->htype, packet->hlen, packet->chaddr), inet_ntoa(to.sin_addr)); ++server_packets_relayed; } return; } /* If giaddr matches one of our addresses, ignore the packet - we just sent it. */ if (out) return; if (!(ip->flags & INTERFACE_DOWNSTREAM)) { log_debug("Dropping request received on %s", ip->name); return; } /* Add relay agent options if indicated. If something goes wrong, * drop the packet. Note this may set packet->giaddr if RFC3527 * is enabled. */ if (!(length = add_relay_agent_options(ip, packet, length, ip->addresses[0]))) return; /* If giaddr is not already set, Set it so the server can figure out what net it's from and so that we can later forward the response to the correct net. If it's already set, the response will be sent directly to the relay agent that set giaddr, so we won't see it. */ if (!packet->giaddr.s_addr) packet->giaddr = ip->addresses[0]; if (packet->hops < max_hop_count) packet->hops = packet->hops + 1; else return; /* Otherwise, it's a BOOTREQUEST, so forward it to all the servers. */ for (sp = servers; sp; sp = sp->next) { if (send_packet((fallback_interface ? fallback_interface : interfaces), NULL, packet, length, ip->addresses[0], &sp->to, NULL) < 0) { ++client_packet_errors; } else { log_debug("Forwarded BOOTREQUEST for %s to %s", print_hw_addr(packet->htype, packet->hlen, packet->chaddr), inet_ntoa(sp->to.sin_addr)); ++client_packets_relayed; } } } #endif /* UNIT_TEST */ /* Strip any Relay Agent Information options from the DHCP packet option buffer. If there is a circuit ID suboption, look up the outgoing interface based upon it. */ int strip_relay_agent_options(struct interface_info *in, struct interface_info **out, struct dhcp_packet *packet, unsigned length) { int is_dhcp = 0; u_int8_t *op, *nextop, *sp, *max; int good_agent_option = 0; int status; /* If we're not adding agent options to packets, we're not taking them out either. */ if (!add_agent_options) return (length); /* If there's no cookie, it's a bootp packet, so we should just forward it unchanged. */ if (memcmp(packet->options, DHCP_OPTIONS_COOKIE, 4)) return (length); max = ((u_int8_t *)packet) + length; sp = op = &packet->options[4]; while (op < max) { switch(*op) { /* Skip padding... */ case DHO_PAD: if (sp != op) *sp = *op; ++op; ++sp; continue; /* If we see a message type, it's a DHCP packet. */ case DHO_DHCP_MESSAGE_TYPE: is_dhcp = 1; goto skip; break; /* Quit immediately if we hit an End option. */ case DHO_END: if (sp != op) *sp++ = *op++; goto out; case DHO_DHCP_AGENT_OPTIONS: /* We shouldn't see a relay agent option in a packet before we've seen the DHCP packet type, but if we do, we have to leave it alone. */ if (!is_dhcp) goto skip; /* Do not process an agent option if it exceeds the * buffer. Fail this packet. */ nextop = op + op[1] + 2; if (nextop > max) return (0); status = find_interface_by_agent_option(packet, out, op + 2, op[1]); if (status == -1 && drop_agent_mismatches) return (0); if (status) good_agent_option = 1; op = nextop; break; skip: /* Skip over other options. */ default: /* Fail if processing this option will exceed the * buffer(op[1] is malformed). */ nextop = op + op[1] + 2; if (nextop > max) return (0); if (sp != op) { size_t mlen = op[1] + 2; memmove(sp, op, mlen); sp += mlen; if (sp > max) { return (0); } op = nextop; } else op = sp = nextop; break; } } out: /* If it's not a DHCP packet, we're not supposed to touch it. */ if (!is_dhcp) return (length); /* If none of the agent options we found matched, or if we didn't find any agent options, count this packet as not having any matching agent options, and if we're relying on agent options to determine the outgoing interface, drop the packet. */ if (!good_agent_option) { ++missing_agent_option; if (drop_agent_mismatches) return (0); } /* Adjust the length... */ if (sp != op) { length = sp -((u_int8_t *)packet); /* Make sure the packet isn't short(this is unlikely, but WTH) */ if (length < BOOTP_MIN_LEN) { memset(sp, DHO_PAD, BOOTP_MIN_LEN - length); length = BOOTP_MIN_LEN; } } return (length); } /* Find an interface that matches the circuit ID specified in the Relay Agent Information option. If one is found, store it through the pointer given; otherwise, leave the existing pointer alone. We actually deviate somewhat from the current specification here: if the option buffer is corrupt, we suggest that the caller not respond to this packet. If the circuit ID doesn't match any known interface, we suggest that the caller to drop the packet. Only if we find a circuit ID that matches an existing interface do we tell the caller to go ahead and process the packet. */ int find_interface_by_agent_option(struct dhcp_packet *packet, struct interface_info **out, u_int8_t *buf, int len) { int i = 0; u_int8_t *circuit_id = 0; unsigned circuit_id_len = 0; struct interface_info *ip; while (i < len) { /* If the next agent option overflows the end of the packet, the agent option buffer is corrupt. */ if (i + 1 == len || i + buf[i + 1] + 2 > len) { ++corrupt_agent_options; return (-1); } switch(buf[i]) { /* Remember where the circuit ID is... */ case RAI_CIRCUIT_ID: circuit_id = &buf[i + 2]; circuit_id_len = buf[i + 1]; i += circuit_id_len + 2; continue; default: i += buf[i + 1] + 2; break; } } /* If there's no circuit ID, it's not really ours, tell the caller it's no good. */ if (!circuit_id) { ++missing_circuit_id; return (-1); } /* Scan the interface list looking for an interface whose name matches the one specified in circuit_id. */ for (ip = interfaces; ip; ip = ip->next) { if (ip->circuit_id && ip->circuit_id_len == circuit_id_len && !memcmp(ip->circuit_id, circuit_id, circuit_id_len)) break; } /* If we got a match, use it. */ if (ip) { *out = ip; return (1); } /* If we didn't get a match, the circuit ID was bogus. */ ++bad_circuit_id; return (-1); } /* * Examine a packet to see if it's a candidate to have a Relay * Agent Information option tacked onto its tail. If it is, tack * the option on. */ int add_relay_agent_options(struct interface_info *ip, struct dhcp_packet *packet, unsigned length, struct in_addr giaddr) { int is_dhcp = 0, mms; unsigned optlen; u_int8_t *op, *nextop, *sp, *max, *end_pad = NULL; int adding_link_select; /* If we're not adding agent options to packets, we can skip this. */ if (!add_agent_options) return (length); /* If there's no cookie, it's a bootp packet, so we should just forward it unchanged. */ if (memcmp(packet->options, DHCP_OPTIONS_COOKIE, 4)) return (length); max = ((u_int8_t *)packet) + dhcp_max_agent_option_packet_length; /* Add link selection suboption if enabled and we're the first relay */ adding_link_select = (add_rfc3527_suboption && (packet->giaddr.s_addr == 0)); /* Commence processing after the cookie. */ sp = op = &packet->options[4]; while (op < max) { switch(*op) { /* Skip padding... */ case DHO_PAD: /* Remember the first pad byte so we can commandeer * padded space. * * XXX: Is this really a good idea? Sure, we can * seemingly reduce the packet while we're looking, * but if the packet was signed by the client then * this padding is part of the checksum(RFC3118), * and its nonpresence would break authentication. */ if (end_pad == NULL) end_pad = sp; if (sp != op) *sp++ = *op++; else sp = ++op; continue; /* If we see a message type, it's a DHCP packet. */ case DHO_DHCP_MESSAGE_TYPE: is_dhcp = 1; goto skip; /* * If there's a maximum message size option, we * should pay attention to it */ case DHO_DHCP_MAX_MESSAGE_SIZE: mms = ntohs(*(op + 2)); if (mms < dhcp_max_agent_option_packet_length && mms >= DHCP_MTU_MIN) max = ((u_int8_t *)packet) + mms; goto skip; /* Quit immediately if we hit an End option. */ case DHO_END: goto out; case DHO_DHCP_AGENT_OPTIONS: /* We shouldn't see a relay agent option in a packet before we've seen the DHCP packet type, but if we do, we have to leave it alone. */ if (!is_dhcp) goto skip; end_pad = NULL; /* There's already a Relay Agent Information option in this packet. How embarrassing. Decide what to do based on the mode the user specified. */ switch(agent_relay_mode) { case forward_and_append: goto skip; case forward_untouched: return (length); case discard: return (0); case forward_and_replace: default: break; } /* Skip over the agent option and start copying if we aren't copying already. */ op += op[1] + 2; break; skip: /* Skip over other options. */ default: /* Fail if processing this option will exceed the * buffer(op[1] is malformed). */ nextop = op + op[1] + 2; if (nextop > max) return (0); end_pad = NULL; if (sp != op) { size_t mlen = op[1] + 2; memmove(sp, op, mlen); sp += mlen; if (sp > max) { return (0); } op = nextop; } else op = sp = nextop; break; } } out: /* If it's not a DHCP packet, we're not supposed to touch it. */ if (!is_dhcp) return (length); /* If the packet was padded out, we can store the agent option at the beginning of the padding. */ if (end_pad != NULL) sp = end_pad; #if 0 /* Remember where the end of the packet was after parsing it. */ op = sp; #endif /* Sanity check. Had better not ever happen. */ if ((ip->circuit_id_len > 255) ||(ip->circuit_id_len < 1)) log_fatal("Circuit ID length %d out of range [1-255] on " "%s\n", ip->circuit_id_len, ip->name); optlen = ip->circuit_id_len + 2; /* RAI_CIRCUIT_ID + len */ if (ip->remote_id) { if (ip->remote_id_len > 255 || ip->remote_id_len < 1) log_fatal("Remote ID length %d out of range [1-255] " "on %s\n", ip->remote_id_len, ip->name); optlen += ip->remote_id_len + 2; /* RAI_REMOTE_ID + len */ } if (adding_link_select) { optlen += 6; } #ifdef RELAY_PORT if (relay_port) { optlen += 2; } #endif /* We do not support relay option fragmenting(multiple options to * support an option data exceeding 255 bytes). */ if ((optlen < 3) ||(optlen > 255)) log_fatal("Total agent option length(%u) out of range " "[3 - 255] on %s\n", optlen, ip->name); /* * Is there room for the option, its code+len, and DHO_END? * If not, forward without adding the option. */ if (max - sp >= optlen + 3) { log_debug("Adding %d-byte relay agent option", optlen + 3); /* Okay, cons up *our* Relay Agent Information option. */ *sp++ = DHO_DHCP_AGENT_OPTIONS; *sp++ = optlen; /* Copy in the circuit id... */ *sp++ = RAI_CIRCUIT_ID; *sp++ = ip->circuit_id_len; memcpy(sp, ip->circuit_id, ip->circuit_id_len); sp += ip->circuit_id_len; /* Copy in remote ID... */ if (ip->remote_id) { *sp++ = RAI_REMOTE_ID; *sp++ = ip->remote_id_len; memcpy(sp, ip->remote_id, ip->remote_id_len); sp += ip->remote_id_len; } /* RFC3527: Use the inbound packet's interface address in * the link selection suboption and set the outbound giaddr * to the uplink address. */ if (adding_link_select) { *sp++ = RAI_LINK_SELECT; *sp++ = 4u; memcpy(sp, &giaddr.s_addr, 4); sp += 4; packet->giaddr = uplink->addresses[0]; log_debug ("Adding link selection suboption" " with addr: %s", inet_ntoa(giaddr)); } #ifdef RELAY_PORT /* draft-ietf-dhc-relay-port-10.txt section 5.1 */ if (relay_port) { *sp++ = RAI_RELAY_PORT; *sp++ = 0u; } #endif } else { ++agent_option_errors; log_error("No room in packet (used %d of %d) " "for %d-byte relay agent option: omitted", (int) (sp - ((u_int8_t *) packet)), (int) (max - ((u_int8_t *) packet)), optlen + 3); } /* * Deposit an END option unless the packet is full (shouldn't * be possible). */ if (sp < max) *sp++ = DHO_END; /* Recalculate total packet length. */ length = sp -((u_int8_t *)packet); /* Make sure the packet isn't short(this is unlikely, but WTH) */ if (length < BOOTP_MIN_LEN) { memset(sp, DHO_PAD, BOOTP_MIN_LEN - length); return (BOOTP_MIN_LEN); } return (length); } #ifdef DHCPv6 #ifndef UNIT_TEST /* * Parse a downstream argument: [address%]interface[#index]. */ static struct stream_list * parse_downstream(char *arg) { struct stream_list *dp, *up; struct interface_info *ifp = NULL; char *ifname, *addr, *iid; isc_result_t status; if (!supports_multiple_interfaces(ifp) && (downstreams != NULL)) log_fatal("No support for multiple interfaces."); /* Decode the argument. */ ifname = strchr(arg, '%'); if (ifname == NULL) { ifname = arg; addr = NULL; } else { *ifname++ = '\0'; addr = arg; } iid = strchr(ifname, '#'); if (iid != NULL) { *iid++ = '\0'; } if (strlen(ifname) >= sizeof(ifp->name)) { usage("Interface name '%s' too long", ifname); } /* Don't declare twice. */ for (dp = downstreams; dp; dp = dp->next) { if (strcmp(ifname, dp->ifp->name) == 0) log_fatal("Down interface '%s' declared twice.", ifname); } /* Share with up side? */ for (up = upstreams; up; up = up->next) { if (strcmp(ifname, up->ifp->name) == 0) { log_info("parse_downstream: Interface '%s' is " "both down and up.", ifname); ifp = up->ifp; break; } } /* New interface. */ if (ifp == NULL) { status = interface_allocate(&ifp, MDL); if (status != ISC_R_SUCCESS) log_fatal("%s: interface_allocate: %s", arg, isc_result_totext(status)); strcpy(ifp->name, ifname); if (interfaces) { interface_reference(&ifp->next, interfaces, MDL); interface_dereference(&interfaces, MDL); } interface_reference(&interfaces, ifp, MDL); } ifp->flags |= INTERFACE_REQUESTED | INTERFACE_DOWNSTREAM; /* New downstream. */ dp = (struct stream_list *) dmalloc(sizeof(*dp), MDL); if (!dp) log_fatal("No memory for downstream."); dp->ifp = ifp; if (iid != NULL) { dp->id = atoi(iid); } else { dp->id = -1; } /* !addr case handled by setup. */ if (addr && (inet_pton(AF_INET6, addr, &dp->link.sin6_addr) <= 0)) log_fatal("Bad link address '%s'", addr); return dp; } /* * Parse an upstream argument: [address]%interface. */ static struct stream_list * parse_upstream(char *arg) { struct stream_list *up, *dp; struct interface_info *ifp = NULL; char *ifname, *addr; isc_result_t status; /* Decode the argument. */ ifname = strchr(arg, '%'); if (ifname == NULL) { ifname = arg; addr = All_DHCP_Servers; } else { *ifname++ = '\0'; addr = arg; } if (strlen(ifname) >= sizeof(ifp->name)) { log_fatal("Interface name '%s' too long", ifname); } /* Shared up interface? */ for (up = upstreams; up; up = up->next) { if (strcmp(ifname, up->ifp->name) == 0) { ifp = up->ifp; break; } } for (dp = downstreams; dp; dp = dp->next) { if (strcmp(ifname, dp->ifp->name) == 0) { log_info("parse_upstream: Interface '%s' is " "both down and up.", ifname); ifp = dp->ifp; break; } } /* New interface. */ if (ifp == NULL) { status = interface_allocate(&ifp, MDL); if (status != ISC_R_SUCCESS) log_fatal("%s: interface_allocate: %s", arg, isc_result_totext(status)); strcpy(ifp->name, ifname); if (interfaces) { interface_reference(&ifp->next, interfaces, MDL); interface_dereference(&interfaces, MDL); } interface_reference(&interfaces, ifp, MDL); } ifp->flags |= INTERFACE_REQUESTED | INTERFACE_UPSTREAM; /* New upstream. */ up = (struct stream_list *) dmalloc(sizeof(*up), MDL); if (up == NULL) log_fatal("No memory for upstream."); up->ifp = ifp; if (inet_pton(AF_INET6, addr, &up->link.sin6_addr) <= 0) log_fatal("Bad address %s", addr); return up; } /* * Setup downstream interfaces. */ static void setup_streams(void) { struct stream_list *dp, *up; int i; isc_boolean_t link_is_set; for (dp = downstreams; dp; dp = dp->next) { /* Check interface */ if (dp->ifp->v6address_count == 0) log_fatal("Interface '%s' has no IPv6 addresses.", dp->ifp->name); /* Check/set link. */ if (IN6_IS_ADDR_UNSPECIFIED(&dp->link.sin6_addr)) link_is_set = ISC_FALSE; else link_is_set = ISC_TRUE; for (i = 0; i < dp->ifp->v6address_count; i++) { if (IN6_IS_ADDR_LINKLOCAL(&dp->ifp->v6addresses[i])) continue; if (!link_is_set) break; if (!memcmp(&dp->ifp->v6addresses[i], &dp->link.sin6_addr, sizeof(dp->link.sin6_addr))) break; } if (i == dp->ifp->v6address_count) log_fatal("Interface %s does not have global IPv6 " "address assigned.", dp->ifp->name); if (!link_is_set) memcpy(&dp->link.sin6_addr, &dp->ifp->v6addresses[i], sizeof(dp->link.sin6_addr)); /* Set interface-id. */ if (dp->id == -1) dp->id = dp->ifp->index; } for (up = upstreams; up; up = up->next) { up->link.sin6_port = local_port; up->link.sin6_family = AF_INET6; #ifdef HAVE_SA_LEN up->link.sin6_len = sizeof(up->link); #endif if (up->ifp->v6address_count == 0) log_fatal("Interface '%s' has no IPv6 addresses.", up->ifp->name); /* RFC 3315 Sec 20 - "If the relay agent relays messages to * the All_DHCP_Servers address or other multicast addresses, * it sets the Hop Limit field to 32." */ if (IN6_IS_ADDR_MULTICAST(&up->link.sin6_addr)) { set_multicast_hop_limit(up->ifp, HOP_COUNT_LIMIT); } } } /* * Add DHCPv6 agent options here. */ static const int required_forw_opts[] = { D6O_INTERFACE_ID, D6O_SUBSCRIBER_ID, #if defined(RELAY_PORT) D6O_RELAY_SOURCE_PORT, #endif D6O_RELAY_MSG, 0 }; /* * Process a packet upwards, i.e., from client to server. */ static void process_up6(struct packet *packet, struct stream_list *dp) { char forw_data[65535]; unsigned cursor; struct dhcpv6_relay_packet *relay; struct option_state *opts; struct stream_list *up; u_int16_t relay_client_port = 0; /* Check if the message should be relayed to the server. */ switch (packet->dhcpv6_msg_type) { case DHCPV6_SOLICIT: case DHCPV6_REQUEST: case DHCPV6_CONFIRM: case DHCPV6_RENEW: case DHCPV6_REBIND: case DHCPV6_RELEASE: case DHCPV6_DECLINE: case DHCPV6_INFORMATION_REQUEST: case DHCPV6_RELAY_FORW: case DHCPV6_LEASEQUERY: case DHCPV6_DHCPV4_QUERY: log_info("Relaying %s from %s port %d going up.", dhcpv6_type_names[packet->dhcpv6_msg_type], piaddr(packet->client_addr), ntohs(packet->client_port)); break; case DHCPV6_ADVERTISE: case DHCPV6_REPLY: case DHCPV6_RECONFIGURE: case DHCPV6_RELAY_REPL: case DHCPV6_LEASEQUERY_REPLY: case DHCPV6_DHCPV4_RESPONSE: log_info("Discarding %s from %s port %d going up.", dhcpv6_type_names[packet->dhcpv6_msg_type], piaddr(packet->client_addr), ntohs(packet->client_port)); return; default: log_info("Unknown %d type from %s port %d going up.", packet->dhcpv6_msg_type, piaddr(packet->client_addr), ntohs(packet->client_port)); return; } /* Build the relay-forward header. */ relay = (struct dhcpv6_relay_packet *) forw_data; cursor = offsetof(struct dhcpv6_relay_packet, options); relay->msg_type = DHCPV6_RELAY_FORW; if (packet->dhcpv6_msg_type == DHCPV6_RELAY_FORW) { if (packet->dhcpv6_hop_count >= max_hop_count) { log_info("Hop count exceeded,"); return; } relay->hop_count = packet->dhcpv6_hop_count + 1; if (dp) { memcpy(&relay->link_address, &dp->link.sin6_addr, 16); } else { /* On smart relay add: && !global. */ if (!use_if_id && downstreams->next) { log_info("Shan't get back the interface."); return; } memset(&relay->link_address, 0, 16); } if (packet->client_port != htons(547)) { relay_client_port = packet->client_port; } } else { relay->hop_count = 0; if (!dp) return; memcpy(&relay->link_address, &dp->link.sin6_addr, 16); } memcpy(&relay->peer_address, packet->client_addr.iabuf, 16); /* Get an option state. */ opts = NULL; if (!option_state_allocate(&opts, MDL)) { log_fatal("No memory for upwards options."); } /* Add an interface-id (if used). */ if (use_if_id) { int if_id; if (dp) { if_id = dp->id; } else if (!downstreams->next) { if_id = downstreams->id; } else { log_info("Don't know the interface."); option_state_dereference(&opts, MDL); return; } if (!save_option_buffer(&dhcpv6_universe, opts, NULL, (unsigned char *) &if_id, sizeof(int), D6O_INTERFACE_ID, 0)) { log_error("Can't save interface-id."); option_state_dereference(&opts, MDL); return; } } /* Add a subscriber-id if desired. */ /* This is for testing rather than general use */ if (dhcrelay_sub_id != NULL) { if (!save_option_buffer(&dhcpv6_universe, opts, NULL, (unsigned char *) dhcrelay_sub_id, strlen(dhcrelay_sub_id), D6O_SUBSCRIBER_ID, 0)) { log_error("Can't save subsriber-id."); option_state_dereference(&opts, MDL); return; } } #if defined(RELAY_PORT) /* * If we use a non-547 UDP source port or if we have received * from a downstream relay agent uses a non-547 port, we need * to include the RELAY-SOURCE-PORT option. The "Downstream * UDP Port" field value in the option allow us to send * relay-reply message back to the downstream relay agent * with the correct UDP source port. */ if (relay_port || relay_client_port) { if (!save_option_buffer(&dhcpv6_universe, opts, NULL, (unsigned char *) &relay_client_port, sizeof(u_int16_t), D6O_RELAY_SOURCE_PORT, 0)) { log_error("Can't save relay-source-port."); option_state_dereference(&opts, MDL); return; } } #else /* Avoid unused but set warning, */ (void)(relay_client_port); #endif /* Add the relay-msg carrying the packet. */ if (!save_option_buffer(&dhcpv6_universe, opts, NULL, (unsigned char *) packet->raw, packet->packet_length, D6O_RELAY_MSG, 0)) { log_error("Can't save relay-msg."); option_state_dereference(&opts, MDL); return; } /* Finish the relay-forward message. */ cursor += store_options6(forw_data + cursor, sizeof(forw_data) - cursor, opts, packet, required_forw_opts, NULL); option_state_dereference(&opts, MDL); /* Send it to all upstreams. */ for (up = upstreams; up; up = up->next) { send_packet6(up->ifp, (unsigned char *) forw_data, (size_t) cursor, &up->link); } } /* * Process a packet downwards, i.e., from server to client. */ static void process_down6(struct packet *packet) { struct stream_list *dp; struct option_cache *oc; struct data_string relay_msg; const struct dhcpv6_packet *msg; struct data_string if_id; #if defined(RELAY_PORT) struct data_string down_port; #endif struct sockaddr_in6 to; struct iaddr peer; /* The packet must be a relay-reply message. */ if (packet->dhcpv6_msg_type != DHCPV6_RELAY_REPL) { if (packet->dhcpv6_msg_type < dhcpv6_type_name_max) log_info("Discarding %s from %s port %d going down.", dhcpv6_type_names[packet->dhcpv6_msg_type], piaddr(packet->client_addr), ntohs(packet->client_port)); else log_info("Unknown %d type from %s port %d going down.", packet->dhcpv6_msg_type, piaddr(packet->client_addr), ntohs(packet->client_port)); return; } /* Inits. */ memset(&relay_msg, 0, sizeof(relay_msg)); memset(&if_id, 0, sizeof(if_id)); #if defined(RELAY_PORT) memset(&down_port, 0, sizeof(down_port)); #endif memset(&to, 0, sizeof(to)); to.sin6_family = AF_INET6; #ifdef HAVE_SA_LEN to.sin6_len = sizeof(to); #endif to.sin6_port = remote_port; peer.len = 16; /* Get the relay-msg option (carrying the message to relay). */ oc = lookup_option(&dhcpv6_universe, packet->options, D6O_RELAY_MSG); if (oc == NULL) { log_info("No relay-msg."); return; } if (!evaluate_option_cache(&relay_msg, packet, NULL, NULL, packet->options, NULL, &global_scope, oc, MDL) || (relay_msg.len < offsetof(struct dhcpv6_packet, options))) { log_error("Can't evaluate relay-msg."); goto cleanup; } msg = (const struct dhcpv6_packet *) relay_msg.data; /* Get the interface-id (if exists) and the downstream. */ oc = lookup_option(&dhcpv6_universe, packet->options, D6O_INTERFACE_ID); if (oc != NULL) { int if_index; if (!evaluate_option_cache(&if_id, packet, NULL, NULL, packet->options, NULL, &global_scope, oc, MDL) || (if_id.len != sizeof(int))) { log_info("Can't evaluate interface-id."); goto cleanup; } memcpy(&if_index, if_id.data, sizeof(int)); for (dp = downstreams; dp; dp = dp->next) { if (dp->id == if_index) break; } } else { if (use_if_id) { /* Require an interface-id. */ log_info("No interface-id."); goto cleanup; } for (dp = downstreams; dp; dp = dp->next) { /* Get the first matching one. */ if (!memcmp(&dp->link.sin6_addr, &packet->dhcpv6_link_address, sizeof(struct in6_addr))) break; } } /* Why bother when there is no choice. */ if (!dp && downstreams && !downstreams->next) dp = downstreams; if (!dp) { log_info("Can't find the down interface."); goto cleanup; } memcpy(peer.iabuf, &packet->dhcpv6_peer_address, peer.len); to.sin6_addr = packet->dhcpv6_peer_address; /* Check if we should relay the carried message. */ switch (msg->msg_type) { /* Relay-Reply of for another relay, not a client. */ case DHCPV6_RELAY_REPL: to.sin6_port = local_port; #if defined(RELAY_PORT) oc = lookup_option(&dhcpv6_universe, packet->options, D6O_RELAY_SOURCE_PORT); if (oc != NULL) { u_int16_t down_relay_port; memset(&down_port, 0, sizeof(down_port)); if (!evaluate_option_cache(&down_port, packet, NULL, NULL, packet->options, NULL, &global_scope, oc, MDL) || (down_port.len != sizeof(u_int16_t))) { log_info("Can't evaluate down " "relay-source-port."); goto cleanup; } memcpy(&down_relay_port, down_port.data, sizeof(u_int16_t)); /* * If the down_relay_port value is non-zero, * that means our downstream relay agent uses * a non-547 UDP source port sending * relay-forw message to us. We need to use * the same UDP port sending reply back. */ if (down_relay_port) { to.sin6_port = down_relay_port; } } #endif /* Fall into: */ case DHCPV6_ADVERTISE: case DHCPV6_REPLY: case DHCPV6_RECONFIGURE: case DHCPV6_RELAY_FORW: case DHCPV6_LEASEQUERY_REPLY: case DHCPV6_DHCPV4_RESPONSE: log_info("Relaying %s to %s port %d down.", dhcpv6_type_names[msg->msg_type], piaddr(peer), ntohs(to.sin6_port)); break; case DHCPV6_SOLICIT: case DHCPV6_REQUEST: case DHCPV6_CONFIRM: case DHCPV6_RENEW: case DHCPV6_REBIND: case DHCPV6_RELEASE: case DHCPV6_DECLINE: case DHCPV6_INFORMATION_REQUEST: case DHCPV6_LEASEQUERY: case DHCPV6_DHCPV4_QUERY: log_info("Discarding %s to %s port %d down.", dhcpv6_type_names[msg->msg_type], piaddr(peer), ntohs(to.sin6_port)); goto cleanup; default: log_info("Unknown %d type to %s port %d down.", msg->msg_type, piaddr(peer), ntohs(to.sin6_port)); goto cleanup; } /* Send the message to the downstream. */ send_packet6(dp->ifp, (unsigned char *) relay_msg.data, (size_t) relay_msg.len, &to); cleanup: if (relay_msg.data != NULL) data_string_forget(&relay_msg, MDL); if (if_id.data != NULL) data_string_forget(&if_id, MDL); } #endif /* UNIT_TEST */ /* * Called by the dispatch packet handler with a decoded packet. */ void dhcpv6(struct packet *packet) { #ifndef UNIT_TEST struct stream_list *dp; /* Try all relay-replies downwards. */ if (packet->dhcpv6_msg_type == DHCPV6_RELAY_REPL) { process_down6(packet); return; } /* Others are candidates to go up if they come from down. */ for (dp = downstreams; dp; dp = dp->next) { if (packet->interface != dp->ifp) continue; process_up6(packet, dp); return; } /* Relay-forward could work from an unknown interface. */ if (packet->dhcpv6_msg_type == DHCPV6_RELAY_FORW) { process_up6(packet, NULL); return; } log_info("Can't process packet from interface '%s'.", packet->interface->name); #endif /* UNIT_TEST */ } #endif /* DHCPv6 */ /* Stub routines needed for linking with DHCP libraries. */ void bootp(struct packet *packet) { return; } void dhcp(struct packet *packet) { return; } #if defined(DHCPv6) && defined(DHCP4o6) isc_result_t dhcpv4o6_handler(omapi_object_t *h) { return ISC_R_NOTIMPLEMENTED; } #endif void classify(struct packet *p, struct class *c) { return; } int check_collection(struct packet *p, struct lease *l, struct collection *c) { return 0; } isc_result_t find_class(struct class **class, const char *c1, const char *c2, int i) { return ISC_R_NOTFOUND; } int parse_allow_deny(struct option_cache **oc, struct parse *p, int i) { return 0; } isc_result_t dhcp_set_control_state(control_object_state_t oldstate, control_object_state_t newstate) { char buf = 0; if (newstate != server_shutdown) return ISC_R_SUCCESS; /* Log shutdown on signal. */ log_info("Received signal %d, initiating shutdown.", shutdown_signal); if (no_pid_file == ISC_FALSE) (void) unlink(path_dhcrelay_pid); if (!no_daemon && dfd[0] != -1 && dfd[1] != -1) { IGNORE_RET(write(dfd[1], &buf, 1)); (void) close(dfd[1]); dfd[0] = dfd[1] = -1; } exit(0); } /*! * * \brief Allocate an interface as requested with a given set of flags * * The requested interface is allocated, its flags field is set to * INTERFACE_REQUESTED OR'd with the given flags, and then added to * the list of interfaces. * * \param name - name of the requested interface * \param flags - additional flags for the interface * * \return Nothing */ void request_v4_interface(const char* name, int flags) { struct interface_info *tmp = NULL; int len = strlen(name); isc_result_t status; if (len >= sizeof(tmp->name)) { log_fatal("%s: interface name too long (is %d)", name, len); } status = interface_allocate(&tmp, MDL); if (status != ISC_R_SUCCESS) { log_fatal("%s: interface_allocate: %s", name, isc_result_totext(status)); } log_debug("Requesting: %s as upstream: %c downstream: %c", name, (flags & INTERFACE_UPSTREAM ? 'Y' : 'N'), (flags & INTERFACE_DOWNSTREAM ? 'Y' : 'N')); memcpy(tmp->name, name, len); interface_snorf(tmp, (INTERFACE_REQUESTED | flags)); interface_dereference(&tmp, MDL); }